diagram.json

# Wokwi Library List
# See https://docs.wokwi.com/guides/libraries

SimpleTimer
DHT sensor library for ESPx
PubSubClient 
ArduinoJson


libraries.txt

#include <WiFi.h>
#include "SimpleTimer.h"
#include <PubSubClient.h>
#include <ArduinoJson.h>

SimpleTimer timer_relay(2000);

const int relay=22;

const char *ssid = "Wokwi-GUEST";
const char *password = "";
const char *mqtt_server = "test.mosquitto.org";

WiFiClient espClient;
PubSubClient client(espClient);

void setup() {
  // put your setup code here, to run once:
  
  Serial.println();
  Serial.print("Підключення до wifi");
  Serial.println(ssid);

  WiFi.mode(WIFI_STA);
  WiFi.begin(ssid, password);

  while (WiFi.status() != WL_CONNECTED)
  {
    delay(500);
    Serial.print(".");
  }

  pinMode(relay, OUTPUT);
  digitalWrite(relay,HIGH);
  Serial.begin(115200);
  Serial.println("Hello, ESP32!");

  client.setServer(mqtt_server, 1883);
  client.setCallback(callback);
}

void reconnect() {
  // Loop until we're reconnected
  while (!client.connected()) {
    Serial.print("Attempting MQTT connection...");
    // Create a random client ID
    String clientId = "mqtt-explorer-584bcd18";
    clientId += String(random(0xffff), HEX);
    // Attempt to connect
    if (client.connect(clientId.c_str())) {
      Serial.println("Connected");
      //client.subscribe("/lab/temp");
      client.subscribe("/lab/data");
      //client.subscribe("Affat/kpp/kelembaban");
      //client.subscribe("Affat/kpp/jarak");
      //client.subscribe("User1/Data");
    } else {
      Serial.print("failed, rc=");
      Serial.print(client.state());
      Serial.println(" try again in 5 seconds");
      // Wait 5 seconds before retrying
      delay(5000);
    }
  }
}


void loop() {
/*
  if (timer_relay.isReady()) 
  {   // Check is ready a first timer
        Serial.println("Timer relay passed");
        if (digitalRead(relay) == LOW)
        {
          digitalWrite(relay,HIGH);
          Serial.println("Relay switch HIGH");
        }
        else
        {
          digitalWrite(relay,LOW);
          Serial.println("Relay switch LOW");
        }
        timer_relay.reset();
  }
*/
  if (!client.connected()) {
    reconnect();
  }
  client.loop();
}



void callback(char* topic, byte* payload, unsigned int length) {
  Serial.print("Message arrived in topic: ");
  Serial.println(topic); 
  Serial.print("Message:");
 
  // Create a character array to store the payload data
  char payloadString[length + 1]; // +1 for null-terminator
  for (int i = 0; i < length; i++) {
    payloadString[i] = (char)payload[i];
  }
  payloadString[length] = '\0'; // Null-terminate the string
  // payload = atoi(payloadString);
 
  String message = String(payloadString);
  Serial.println("payloadString as message:"+ message);

  // Print the payload data
  //Serial.println("payloadString:"+ payloadString);

  StaticJsonDocument<1000> Json;
  //DynamicJsonDocument Json(1500);
  deserializeJson(Json, message);
  JsonObject JsonObj = Json.as<JsonObject>();
  String content = JsonObj[String("content")];
  Serial.println("Income content:"+ content);
  // parse {"type":"message","content":"Temperature:25.20,Humidity:55.50"}
  int posOfdiv = content.indexOf(",");
  String TempString = content.substring(0, posOfdiv);
  Serial.println("Income TempString:"+ TempString);
  posOfdiv = TempString.indexOf(":");
  String Temp = TempString.substring(posOfdiv+1,TempString.length());
  Serial.println("Income Temp:"+ Temp);

  // Convert Temp String to an integer
  float fValue = atof(Temp.c_str());
 
  // Print the payload data as an integer
  Serial.println("Payload Temperature value as float:"+ String(fValue));
  //Serial.println(fValue);

  if (strcmp(topic, "/lab/data") == 0) 
  {
    Serial.println("Temp:"+String(fValue));
    if (fValue > 27)
    {
      digitalWrite(relay,LOW);    
    }
    else
    {
      digitalWrite(relay,HIGH);    
    }
  }
}
 

sketch.ino

Downloaded from https://wokwi.com/projects/397166645355253761

Simulate this project on https://wokwi.com
